Experimental analysis of normal spark discharge voltage and current with a RC-type generator in micro-EDM

This paper focused on the experimental analysis of the discharge voltage and current waveforms in micro-EDM with a RC-type generator. A quasi-maintaining voltage assumption was proposed, and the spark gap discharge voltage was modeled as a voltage source in a first-order liner form. The discharge current and the discharge capacitor voltage under different machining conditions were calculated and compared with the real experimental waveforms of good and bad conductive workpiece, respectively. For the good conductive materials, the discharge voltage looked more like a constant maintaining voltage, and for the bad conductive materials, a low resistive ceramics composite and P-type monocrystalline silicon, the gap discharge voltage featured a relatively high average value and a relatively large variation slope rate. Based on the comparisons, the proposed discharge gap model and its simplification simulated the real discharge waveform and can be used for pulse discrimination and pulse energy prediction in micro-EDM.